I have a Core2Quad Q8200 (2.3GHz) with 4GB of RAM, a 512MB PCIe video card, and a SATA-2 HD. Yet it still isn't fast enough to edit 720i/p video in Sony Vegas or Adobe Premiere/Aftereffects. My RAM usage never peaks over 1.6GB, but my CPU cores make it to 95% quick!
Right now the preview panes in all these programs lag to bad to actually work on the videos. I get to see 1-3 frames every second or two! So how fast do I have to go? At what point will my CPU be fast enough to actually edit these videos? I have to assume that regular people and their regular sub $2k computers can actually work with this footage.
Another way to answer this is, how fast is the PC you used to edit videos?
I'ts worth noting that now that I have Adobe Pre/AF CS4 I am more interested in getting that working than my older Vegas 6. If you didn't have to re-run RAM preview every, single, time you made one change it would be my answer. But since I like to test many filters and effects before choosing one - I have to re-render a 1-sec section of footage over-and-over and it drives me nuts waiting.
Perhaps a motherboard with Dual Xeon chips or something would be able to handle this. It would probably be as much as a dual-crossfire setup and would also speed up other applications.
Update: How fast is the PC you use to edit HD videos (+720p) in Vegas or Premiere?